JSON的用法

最新推荐文章于 2021-08-17 22:07:55 发布

原创最新推荐文章于 2021-08-17 22:07:55 发布 · 4.2k 阅读

2 ·

CC 4.0 BY-SA版权

文章标签：

#json #character #ajax #parameters #javascript #servlet

本文介绍如何使用JSON格式进行数据交互，包括JavaScript中的JSON操作、通过AJAX获取JSON数据及使用Java处理JSON请求的过程。展示了JSON数据的构造、解析以及与Web服务之间的通信。

var user =
{
"username":"andy",
"age":20,
"info": { "tel": "123456", "cellphone": "98765"},
"address":
[
{"city":"beijing","postcode":"222333"},
{"city":"newyork","postcode":"555666"}
]
}
alert(user.username);
alert(user.age);
alert(user.info.cellphone);
alert(user.address[0].city);
alert(user.address[0].postcode);
}
JSON
var user =
{
"username":"andy",
"age":20,
"info": { "tel": "123456", "cellphone": "98765"},
"address":
[
{"city":"beijing","postcode":"222333"},
{"city":"newyork","postcode":"555666"}
]
}
alert(user.username);
alert(user.age);
alert(user.info.cellphone);
alert(user.address[0].city);
alert(user.address[0].postcode);
user.username = "Tom";
alert(user.username);
}
JSON提供了 json.js包，下载 http://www.json.org/json.js 后，将其引入然后就可以简单的使用object. toJSONString()转换成 JSON数据。

js 代码
1. function showCar() {
2. var carr = new Car("Dodge", "Coronet R/T", 1968, "yellow");
3. alert(carr.toJSONString());
4. }
6. function Car(make, model, year, color) {
7. this.make = make;
8. this.model = model;
9. this.year = year;
10. this.color = color;
11. }
JSON
var str = '{ "name": "Violet", "occupation": "character" }';
var obj = eval('(' + str + ')');
alert(obj.toJSONString());
}
var str = '{ "name": "Violet", "occupation": "character" }';
var obj = str.parseJSON();
alert(obj.toJSONString());
}
JSONajaxajax.JSONTest1.java));
ajax
var url = "/MyWebApp/JSONTest1";
var mailAjax = new Ajax.Request(
url,
{
method: 'get',
onComplete: jsonResponse
}
);
}
function jsonResponse(originalRequest) {
alert(originalRequest.responseText);
var myobj = originalRequest.responseText.parseJSON();
alert(myobj.name);
}
1.5.1.js JSON json.js, 修改上面的方法
JSONjson.jar)
alert(originalRequest.responseText);
var myobj = originalRequest.responseText.evalJSON(true);
alert(myobj.name);
}
JSON还提供了java的jar包 http://www. json.org/java/index.html API也很简单，下面举个例子

在javascript中填加请求参数

js 代码
1. function sendRequest() {
2. var carr = new Car("Dodge", "Coronet R/T", 1968, "yellow");
3. var pars = "car=" + carr.toJSONString();
5. var url = "/MyWebApp/JSONTest1";
6. var mailAjax = new Ajax.Request(
7. url,
8. {
9. method: 'get',
10. parameters: pars,
11. onComplete: jsonResponse
12. }
13. );
14. }
使用 JSON 请求字符串就可以简单的生成JSONObject 并进行解析,修改

void doService(HttpServletRequest request, HttpServletResponse response) throws IOException {
String s3 = request.getParameter("car");
try {
JSONObject jsonObj = new JSONObject(s3);
System.out.println(jsonObj.getString("model"));
System.out.println(jsonObj.getInt("year"));
} catch (JSONException e) {
e.printStackTrace();
}
response.getWriter().print("{ /"name/": /"Violet/", /"occupation/": /"character/" }");
}
同样可以使用JSONObject 生成 JSON 字符串，修改servlet

java 代码
1. private void doService(HttpServletRequest request, HttpServletResponse response) throws IOException {
2. String s3 = request.getParameter("car");
3. try {
4. JSONObject jsonObj = new JSONObject(s3);
5. System.out.println(jsonObj.getString("model"));
6. System.out.println(jsonObj.getInt("year"));
7. } catch (JSONException e) {
8. e.printStackTrace();
9. }
11. JSONObject resultJSON = new JSONObject();
12. try {
13. resultJSON.append("name", "Violet")
14. .append("occupation", "developer")
15. .append("age", new Integer(22));
16. System.out.println(resultJSON.toString());
17. } catch (JSONException e) {
18. e.printStackTrace();
19. }
20. response.getWriter().print(resultJSON.toString());
21. }
js 代码
1. function jsonResponse(originalRequest) {
2. alert(originalRequest.responseText);
3. var myobj = originalRequest.responseText.evalJSON(true);
4. alert(myobj.name);
5. alert(myobj.age);
6. }